Why China is Developing Space-Based Solar Power Stations
If proven the technology could provide limitless amounts of clean energy.
Thanks to another talk by Chinese space industry veteran Long Lehao (龙乐豪) in October 2024, partly reshared by the South China Morning Post in January, headlines have been abuzz with news of China’s plans for space-based solar power stations. No doubt you have probably seen some of this news with headlines like ‘China announces plans to build ‘Manhattan Project” solar array in space’, ‘China plans to build enormous solar array in space’, ‘China's Plans to Produce Renewable Energy in Space’, and ‘China to launch one-kilometre-wide solar farm into space’. Two key parts of Long’s talk on space-based solar power were:
“We are working on this project now. It is as significant as moving the Three Gorges Dam to a geostationary orbit 36,000km above the Earth. This is an incredible project to look forward to.”
“Imagine installing a solar array 1km wide along the 36,000km geostationary orbit. The energy collected in one year would be equivalent to the total amount of oil that can be extracted from the Earth.”
Previous talks by Long in recent years have also highlighted the space-based solar power project in relation to new-generation launch vehicles, like the Long March 5, Long March 10, and Long March 9.
Space-based solar power stations stand to revolutionize power generation if achieved, with Long pointing out it being equivalent to putting the Three Gorges Dam (三峡大坝) into space with each station launched. The Three Gorges Dam is already an energy mega-project and generates approximately one hundred billion Kilowatt-hours of power annually.
So what is space-based solar power?
To keep it short and somewhat simple, space-based solar power (SBSP) or space solar power stations (SSPS) are a concept for collecting energy in space using satellites and transmitting it wirelessly down to Earth. Outside of the atmosphere solar panels receive near uninterrupted sight of the sun and generate power more efficiently thanks to the lack of an atmosphere. SBSP solar power plans usually consist of a space and ground segment working together.
The space segment will include large solar power collection satellites placed in geostationary and other high-altitude orbits. These satellites can collect energy and stay over one specific area. Instead of keeping this energy onboard, the satellites convert it into microwaves or laser beams and direct it toward Earth. This wireless power transmission method offers efficient power delivery while removing the requirements for long-distance physical infrastructure.
A ground segment will include infrastructure to receive transmitted power and convert it for use on a national grid. The most critical component of these is a series of large antennas that can revive the energy and convert it into a grids electrical standard for transmission. Also part of the ground segment are various management and control facilities to ensure reliable, safe, and routine operations of the power collection satellites.
If space-based solar power is realized it could offer a continuous, renewable, and scalable source of electricity to further reduce reliance on fossil fuels.
Why is China pursuing SBSP?
Quite simply, to reduce carbon emissions and to meet net-zero goals. Back in 2020 at the United Nations, President Xi Jinping (习近平) announced China’s plans to peak the nation’s carbon emissions by 2030 and to be net-zero by 2060.
So far thanks to the rollout of cheap and mass-produced green energy solutions emissions are set to peak years ahead of schedule, with some saying emissions peaked in 2023 and plateaued in 2024. But as the world’s largest developing nation energy demands are set to grow as China further modernizes its economy through new high-quality but power-hungry industries, and improves its 1.4 billion citizens’ standard of living.
Due to geography it’s not possible to build more Three Gorges-sized dams, cover vast swaths of land in solar panels, or fill offshore shipping lanes with wind turbines to meet growing energy needs. Nuclear fission and fusion can help generate large amounts of power but both of these facilities are usually built a distance away from large urban centers, due to various unfortunate accidents, and near a source of cooling water.
That’s where SBSP comes in. Thanks to its high energy efficiency, ground-side infrastructure can be smaller than that of vast wind or Earth-based solar power farms. In addition, thanks to the vastness of space it’s simpler to launch more power stations into a variety of high orbits that stay near a desired area above the surface.
Off of Earth, SBSP can also be used to power bases on the Moon, such as those for mining large amounts of rare resources, and for exploration missions in the outer solar system where solar panels may be less effective. SBSP may also be a critical stepping-stone technology for a Dyson sphere or swarm.
What progress has been made?
Much of the work on SBSP is still limited to discussion within academic journals and papers as well as small-scale tests on the ground. But, here is a rough timeline of China’s progress so far and in coming years on SBSP based on what I could find:
2008: Space-based solar power is listed as a key research program.
2013: Proposals for SBSP were approved for development and testing.
2014: Various feasibility studies were conducted by national organizations and experts and a roadmap was approved.
~2019: Construction begins of a test facility in Bishan (璧山区), Chongqing (重庆).
~2021: Construction of experimental industrial base begins in Bishan.
August 2021: 300-meter line-of-sight microwave transmission test.
June 2022: Xidian University (西安电子科技大学) completed a full system test with its prototype receiver in Xi’an (西安市), Shaanxi Province (陕西).
2027/2028: Low Earth orbit mission to demonstrate power generation of approximately 10 kilowatts and transferring of energy down to Earth.
2030: Geostationary orbit mission to demonstrate megawatt level power generating and beaming of power back to Earth.
2035: Deployment of stations capable of generating 10 megawatts of power.
2040: First gigawatt-level station may be deployed.
2050: Deployment of stations capable of generating 2 gigawatts of power.
If you know of any other events that should be on the timeline please contact me.
How will China deploy SBSP?
Few details about the deployment and construction of space-based solar power stations have been shared at this stage in the project development. But some predictions can be made based on active and in-development launch vehicles.
For launching the low Earth orbit demonstration mission in 2028, it is likely that the mission will launch on a Long March 5B thanks to its proven reliability, 25,000 kilograms payload capacity, and massive payload fairing volume. Depending on the schedule of the crewed lunar program, the geostationary orbit demonstration mission in 2030 could launch on the Long March 10 thanks to its estimated, not officially stated, capacity to send between 30,000 to 40,000 kilograms to a geostationary transfer orbit and in a possible large fairing like that of the Long March 5 series, currently expected for building lunar space stations.
In the long term of deployment, Long Lehao has said repeatedly that the Long March 9 will be utilized for launching the massive amounts of hardware needed, thanks to its payload capacity of 150,000 kilograms to low Earth orbit or 54,000 kilograms to a lunar transfer orbit. Despite being a massive rocket, 114 meters tall and 10.6 meters wide, the Long March 9 is expected to be quite cost-efficient thanks to the reuse of the first-stage, which has thirty YF-215 engines. With potential second-stage reuse also being explored.